A conventional shielded surface mount electrical connector includes a dielectric (plastic) housing having a plurality of terminal-receiving cavities or passages, with a plurality of terminals received in the passages. A metal shield surrounds a substantial portion of the housing to protect at least the mating portions of the terminals from RF and EMI interference as well as protecting the surroundings from interference radiating from the connector, itself. The housing is mounted to the surface of a printed circuit board, and the terminals have tail portions for surface mounting to circuit pads on the board. In some applications, the housing has no mounting feet or boardlocks extending into holes in the printed circuit board to secure it to the board.
In some systems for using a surface mount electrical connector as described above, the metal shield of the connector is grounded to ground circuit traces on the printed circuit board. In some applications, means are provided for polarizing the connector relative to the board to ensure proper orientation of the connector on the board. In other applications, the connectors are used in pairs, such as mating plug and receptacle connectors, both of which have protective metal shields which are commoned to each other when the connectors are mated. Further, the mating connectors both may be surface mounted to printed circuit boards to provide a board-to-board interconnection. Still other applications have a plurality of connectors mounted to one side of the same printed circuit board, and the connectors are joined by connecting bars or braces.
The present invention is directed to providing various improvements in surface mount electrical connectors, particularly shielded connectors of the character described. For instance, grounding pins on the metal shield of the connector are used to polarize the connector relative to the board, whereby the pins perform an efficient dual function of grounding the shield and polarizing the connector.